Wind turbines are used to produce electrical energy using a renewable resource and without combusting a fossil fuel. Generally, a wind turbine converts kinetic energy from the wind into electrical power. A horizontal-axis wind turbine includes a tower, a nacelle located at the apex of the tower, and a rotor having a plurality of blades and supported in the nacelle by means of a shaft. The shaft couples the rotor either directly or indirectly with a generator, which is housed inside the nacelle. Consequently, as wind forces the blades to rotate, electrical energy is produced by the generator.
In addition to these components, a wind turbine also includes a number of components for regulating the electrical energy produced by the wind turbine. For example, wind turbines often include a transformer, converter, and other electrical components that regulate the electrical energy so that it may be fed to a power grid in a certain manner. These electrical components can be relatively large, heavy items and are expected to become even larger and heavier as wind turbines and their power production continues to increase. These electrical components are typically located in the nacelle adjacent to, for example, the generator. However, as the size of these components increases and the space within the nacelle becomes more limited, alternative locations for the transformer, converter, and other components have been considered. In some wind turbine designs, for example, these components have been located within the tower, and more specifically, adjacent the base of the tower.
The working life of many of these electrical components is less than the working life of the wind turbine. In this regard, the electrical transformer in the wind turbine may have a working life of about twelve years while the wind turbine itself (e.g., blades, tower, etc.) may be designed for a working life of about twenty years. Accordingly, wind turbine designers and manufacturers have to make allowances for removing and replacing these electrical components during the working life of the wind turbine. However, it can be difficult, time consuming, and expensive to remove and replace these various components. For example, when these components are located in the nacelle, large and expensive cranes are typically used to remove and replace the components. When these components are located adjacent the bottom of the tower, expensive and complex internal crane systems must be included within the tower to allow the components to be moved through the door or hatch way typically located at the base of the tower. In any event, component removal and replacement is not easily achieved.
WO 2014/082643 provides a transport system having a track and a carriage movably coupled to the track for moving wind turbine components into and out of the wind turbine through an opening in the wind turbine tower. However, the disclosed transport system and associated method requires that the wind turbine be equipped with an internal winch system, typically supported by the inner wall of the tower, for lowering and/or raising the wind turbine components vertically within the wind turbine tower.
While such a system is successful for its intended purpose, wind turbine designers and manufacturers continually strive to improve upon apparatuses and methods associated with the operation and maintenance of a wind turbine. Aspects of the present invention provide certain improvements to current systems and methods associated with wind turbine maintenance.